My problem is when the bus sat for a few weeks, the front left brake locked on. A few shifts from forward to reverse broke it free, once I figured out what was going on, but Im not crazy about doing that. Gonna pull the wheel this week for the beginning of my first brake r/r. Any ideas what causes something like this ?

Travelingfools, I would remove wheel and brake drum and check brake shoe return springs. Also pull the pin on th brake linkage and check to see cam rotates freely, there are grease fittings on these. Someone with more smarts will give you more ideas. Block up for safety. Tom Y